SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f17f6b714e043f5446903fcd72c7f0a6caa3cbd2fba194cc7282315211b2c6ab' 
  AND token = '/ZZhgJh7UQ5zyNj7PxZnVQtG0NOWUpxLrFs7QxWvMRo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}